U.S. patent application number 11/097031 was filed with the patent office on 2006-10-05 for vending machine door monitoring system.
This patent application is currently assigned to Cantaloupe Systems, Inc. (In Counterpart). Invention is credited to Anant Agrawal, Mandeep S. Arora, A. Louis Beaudoin, Fred Cheng, Eric M. Chu.
Application Number | 20060220845 11/097031 |
Document ID | / |
Family ID | 37054081 |
Filed Date | 2006-10-05 |
United States Patent
Application |
20060220845 |
Kind Code |
A1 |
Agrawal; Anant ; et
al. |
October 5, 2006 |
Vending machine door monitoring system
Abstract
A vending machine door monitoring system for an audit system is
provided. This door monitoring system may utilize the same door
switch utilized by the vending machine controller (VMC) in order to
detect the state of an access door for the vending machine. This
door monitoring system may have a separate power supply for
applying a back-up voltage to a door circuit in the event that the
VMC fails to supply the voltage. The door monitoring system may be
further configured to detect a state of the door circuit regardless
of the order in which the terminals from the door switch are
coupled to the audit system.
Inventors: |
Agrawal; Anant; (Diamond
Bar, CA) ; Beaudoin; A. Louis; (Oakland, CA) ;
Arora; Mandeep S.; (Danville, CA) ; Cheng; Fred;
(Aliso Viejo, CA) ; Chu; Eric M.; (Laguna Niguel,
CA) |
Correspondence
Address: |
MACPHERSON KWOK CHEN & HEID LLP
1762 TECHNOLOGY DRIVE, SUITE 226
SAN JOSE
CA
95110
US
|
Assignee: |
Cantaloupe Systems, Inc. (In
Counterpart)
|
Family ID: |
37054081 |
Appl. No.: |
11/097031 |
Filed: |
March 31, 2005 |
Current U.S.
Class: |
340/545.1 ;
340/5.9 |
Current CPC
Class: |
G07F 9/026 20130101;
G08B 13/08 20130101; G07F 19/208 20130101 |
Class at
Publication: |
340/545.1 ;
340/005.9 |
International
Class: |
G08B 13/08 20060101
G08B013/08 |
Claims
1. An audit system for a vending machine system comprising a
housing including a door having a closed state and an open state, a
door switch, and a vending machine controller (VMC) coupled to the
door switch via a door circuit, said VMC applying a voltage across
the door switch, said audit system comprising: an auxiliary circuit
coupled to the door circuit; and an audit control system configured
to detect the status of the door switch by monitoring the voltage
from the VMC, wherein the audit control system is configured such
that if the audit control system detects cessation of the voltage
from the VMC, the audit control system applies an auxiliary voltage
across the door switch to detect the status of the door switch.
2. The system of claim 1, further comprising: a battery for
supplying the auxiliary voltage across the door switch.
3. The system of claim 1, wherein: said audit control system is
configured to perform an initialization process in which the audit
control system determines a state of the door circuit corresponding
to the open state of the door.
4. The system of claim 3, wherein: said audit control system
performs the initialization process at startup.
5. The system of claim 1, wherein: the VMC comprises a voltage
terminal and a ground terminal; and the audit system comprises a
first input terminal and a second input terminal coupled to the
voltage terminal and the ground terminal, said audit control system
being configured to monitor the voltage passing through the door
switch regardless of whether the first input terminal is coupled to
the voltage terminal or the ground terminal.
6. The system of claim 5, wherein: the audit system comprises a
sensor circuit coupled to the voltage terminal and the ground
terminal, said sensor circuit configured to pull a positive voltage
to a monitoring logic to monitor the voltage passing through the
door switch.
7. The system of claim 1, wherein: said audit system further
comprises a communications interface and is configured to transmit
an open door status message to a host system via the communications
interface upon detection of the open state of the door.
8. The system of claim 7, wherein: said audit system is further
configured to transmit a door status update message to the host
system via the communications interface after a predetermined
period of time following the transmission of the open door status
message.
9. The system of claim 8, wherein: said door status update message
comprises an indication of a current state of the door and the
length of time the door has been in the current state.
10. A method of monitoring operation of a vending machine system,
said method comprising: monitoring a door circuit between a first
power source and a door switch, said door switch engaging and
access door for the vending machine system; in response to a
cessation of a voltage from the first power source, applying a
voltage from a second power source and continuing to monitor the
door circuit between the first power source and the door
switch.
11. The method of claim 10, further comprising: performing an
initialization process in which a state of the door circuit
corresponding to the open state of the door is determined.
12. The method of claim 11, wherein: said initialization process is
performed at startup of an audit system.
13. The method of claim 10, wherein: said monitoring the door
circuit comprises connecting an audit system to the door circuit,
said audit system automatically detecting a voltage line from the
first power source.
14. The method of claim 13, wherein: the audit system comprises a
sensor circuit coupled to a voltage terminal and a ground terminal,
said sensor circuit configured to pull a positive voltage to a
monitoring logic to monitor the voltage passing through the door
switch.
15. The method of claim 10, further comprising: upon detection of
an open state of the access door, transmitting an open door status
message to a host system via a communications interface.
16. The method of claim 15, further comprising: transmitting a door
status update message to the host system via the communications
interface after a predetermined period of time following the
transmission of the open door status message.
17. The method of claim 16, wherein: said door status update
message comprises an indication of a current state of the door and
the length of time the door has been in the current state.
18. A method of operating a vending machine system, comprising:
monitoring a door circuit coupling a door switch and a vending
machine controller (VMC) using an audit system; detecting a
cessation of voltage in the door circuit; and applying an auxiliary
voltage to the door circuit to detect a status of the door
switch.
19. The method of claim 18, wherein: performing an initialization
process in which a state of the door circuit corresponding to the
open state of the door is determined.
20. The method of claim 19, wherein: said initialization process is
performed at startup of an audit system.
21. The method of claim 18, wherein: said monitoring the door
circuit comprises connecting an audit system to the door circuit,
said audit system automatically detecting a voltage line from the
first power source.
22. The method of claim 21, wherein: the audit system comprises a
sensor circuit coupled to a voltage terminal and a ground terminal,
said sensor circuit configured to pull a positive voltage to a
monitoring logic to monitor the voltage passing through the door
switch.
23. The method of claim 18, further comprising: upon detection of
an open state of the access door, transmitting an open door status
message to a host system via a communications interface.
24. The method of claim 23, further comprising: transmitting a door
status update message to the host system via the communications
interface after a predetermined period of time following the
transmission of the open door status message.
25. The method of claim 24, wherein: said door status update
message comprises an indication of a current state of the door and
the length of time the door has been in the current state.
26. A vending machine system, comprising: a housing including a
door having a closed state and an open state; a door switch; a
first means for applying a voltage across the door switch and for
detecting a state of the door switch; and a second means for
detecting the state of the door switch, wherein said second means
applies an auxiliary voltage across the door switch in response to
detection of a cessation of the voltage applied by the first
means.
27. The system of claim 26, further comprising: a battery for
supplying the auxiliary voltage across the door switch.
28. The system of claim 26, wherein: said second means is
configured to perform an initialization process in which the second
means determines a state of the door switch corresponding to the
open state of the door.
29. The system of claim 28, wherein: said second means performs the
initialization process at startup.
30. The system of claim 26, wherein: said first means comprises a
voltage terminal and a ground terminal; and said second means
comprises a first input terminal and a second input terminal
coupled to the voltage terminal and the ground terminal, said
second means being configured to monitor the voltage passing
through the door switch regardless of whether the first input
terminal is coupled to the voltage terminal or the ground
terminal.
31. The system of claim 30, wherein: said second means comprises a
sensor circuit coupled to the voltage terminal and the ground
terminal, said sensor circuit configured to pull a positive voltage
to a monitoring logic to monitor the voltage passing through the
door switch.
32. The system of claim 26, further comprising: a means for
generating an open door status message to be transmitted to a host
system via a communications interface upon detection of the open
state of the door.
33. The system of claim 32, wherein: said means for generating the
open door status message is further configured to transmit a door
status update message to the host system via the communications
interface after a predetermined period of time following the
transmission of the open door status message.
34. The system of claim 33, wherein: said door status update
message comprises an indication of a current state of the door and
the length of time the door has been in the current state.
Description
BACKGROUND
[0001] Vending machines have long been used for selling products to
consumers. In the past, vending machine managers needed to send
human operators to personally visit each vending machine in order
to check on the status of the vending machine, to retrieve the
collected cash, and to restock the vending machine with new
products to replace the products that had been sold. These vending
machines may be provided with a door switch, which would indicate
to the vending machine controller whether the access door is open
or closed. Many vending machines are configured such that when the
vending machine controller detects that the door is open, the
vending machine enters into "service mode."
[0002] A problem arises when there is a failure with the door
switch such that the vending machine controller believes that the
door is open when, in fact, the door is closed. When the vending
machine is in service mode, customers are typically unable to
purchase products from the vending machine. Thus, a malfunction of
the door switch can prevent any sales from occurring, even when the
vending machine is otherwise functioning properly. Even worse, when
some vending machines are in service mode, a user may be able to
reset the pricing of the products in the vending machine or cause
the vending machine to vend product for free.
[0003] Recently, vending machines have been equipped with
monitoring systems for monitoring the status of the vending machine
and for keeping track of product sales and restocking. Even more
recently, vending machines have been provided with monitoring
systems capable of transmitting information regarding the status of
the vending machine to a central server. In many cases, existing
vending machines are retrofitted with these types of monitoring
systems. These monitoring systems may enable the vending machine to
report to a central host when a "door open" state is detected. This
can help operators to identify machines with malfunctioning door
switches. However, due to the wide variety of vending machine
designs, the retrofitting process can be difficult and
time-consuming, and require skilled service personnel for the
installation.
[0004] Accordingly, it would be desirable to provide a vending
machine monitoring system that can be easily installed at low
cost.
SUMMARY
[0005] A vending machine door monitoring system for an audit system
is provided. This door monitoring system may utilize the same door
switch utilized by the vending machine controller (VMC) in order to
detect the state of an access door for the vending machine. This
door monitoring system may have a separate power supply for
applying a back-up voltage to a door circuit in the event that the
VMC fails to supply the voltage. The door monitoring system may be
further configured to detect a state of the door circuit regardless
of the order in which the terminals from the door switch are
coupled to the audit system.
[0006] In accordance with embodiments of the present invention, an
audit system for a vending machine system is provided. The vending
machine comprises a housing including a door having a closed state
and an open state, a door switch, and a vending machine controller
(VMC) coupled to the door switch via a door circuit, said VMC
applying a voltage across the door switch. The audit system
comprises: an auxiliary circuit coupled to the door circuit; and an
audit control system configured to detect the status of the door
switch by monitoring the voltage from the VMC, wherein the audit
control system is configured such that if the audit control system
detects cessation of the voltage from the VMC, the audit control
system applies an auxiliary voltage across the door switch to
detect the status of the door switch.
[0007] In accordance with other embodiments of the present
invention, a method of monitoring operation of a vending machine
system is provided, said method comprising: monitoring a door
circuit between a first power source and a door switch, said door
switch engaging and access door for the vending machine system; in
response to a cessation of a voltage from the first power source,
applying a voltage from a second power source and continuing to
monitor the door circuit between the first power source and the
door switch.
[0008] In accordance with other embodiments of the present
invention, a method of operating a vending machine system is
provided, comprising: monitoring a door circuit coupling a door
switch and a vending machine controller (VMC) using an audit
system; detecting a cessation of voltage in the door circuit; and
applying an auxiliary voltage to the door circuit to detect a
status of the door switch.
[0009] In accordance with other embodiments of the present
invention, a vending machine system is provided, comprising: a
housing including a door having a closed state and an open state; a
door switch; a first means for applying a voltage across the door
switch and for detecting a state of the door switch; and a second
means for detecting the state of the door switch, wherein said
second means applies an auxiliary voltage across the door switch in
response to detection of a cessation of the voltage applied by the
first means.
[0010] Other features and aspects of the invention will become
apparent from the following detailed description, taken in
conjunction with the accompanying drawings which illustrate, by way
of example, the features in accordance with embodiments of the
invention. The summary is not intended to limit the scope of the
invention, which is defined solely by the claims of the issued
patent.
DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 shows a vending machine system, in accordance with
embodiments of the present invention.
[0012] FIG. 2 is a simplified schematic illustrating the operation
of a conventional door switch.
[0013] FIG. 3 shows the use of a door sensor with an existing door
switch, in accordance with embodiments of the present
invention.
[0014] FIG. 4 shows a door sensor that can continue to monitor the
status of an access door in the event of a power failure, in
accordance with embodiments of the present invention.
[0015] FIG. 5 shows a door sensor for automatically detecting the
voltage line, in accordance with embodiments of the present
invention.
[0016] FIG. 6 shows a method of monitoring operation of a vending
machine system, in accordance with embodiments of the present
invention.
DETAILED DESCRIPTION
[0017] In the following description, reference is made to the
accompanying drawings which illustrate several embodiments of the
present invention. It is understood that other embodiments may be
utilized and mechanical, compositional, structural, electrical, and
operational changes may be made without departing from the spirit
and scope of the present disclosure. The following detailed
description is not to be taken in a limiting sense, and the scope
of the embodiments of the present invention is defined only by the
claims of the issued patent.
[0018] Some portions of the detailed description which follows are
presented in terms of procedures, steps, logic blocks, processing,
and other symbolic representations of operations on data bits that
can be performed on computer memory. Each step may be performed by
hardware, software, firmware, or combinations thereof.
[0019] FIG. 1 is a block diagram of an arrangement for a vending
machine monitoring system, in accordance with embodiments of the
present invention. A vending machine system 100 is coupled to a
host system 160 via a wide area network 162, such as the Internet.
The vending machine system 100 comprises a vending machine
controller (VMC) 110 and an audit system 140. The audit system 140
includes a communications interface 142 which provides a
communications link to the network 162 and allows the audit system
140 to transmit operational data regarding the vending machine
system 100 to the host system 160. This communications link may
comprise, e.g., a wireless communications link. A remote management
system 164 may also be provided to allow a user to access the
operational data regarding the vending machine on host system 160
and to manage the operation of the vending machine system 100.
[0020] The vending machine system 100 includes a product storage
portion 102, which stores the various types of products to be sold
by the vending machine system 100 in one or more product storage
compartments. These product storage compartments are sometimes
referred to as "coils", in reference to the coil-shaped wire often
used in conventional vending machines to control the delivery of
products to customers.
[0021] The vending machine system 100 also includes a payment
module 106, which may be configured to receive payment from a user
in various forms, including, e.g., bills, coins, credit card, debit
card, smartcard, wireless authorization (e.g., via cell phone), or
the like. A user interface 108 is provided for allowing a user to
make product selections. Typically, the user interface 108 will
include a plurality of buttons, each button corresponding to a
particular type of product available for sale. In other
embodiments, the user interface 108 will include a keypad or
touchscreen for entering product selections. The payment module 106
and user interface 108 are coupled to the VMC 110, which controls
the operation of the vending machine system 100. During normal use,
when a user has provided sufficient payment via the payment module
106 and makes a product selection via the user interface 108, the
VMC 110 activates a product delivery mechanism 104, which retrieves
the selected product from the appropriate product storage
compartment and delivers the product to the user. One or more
supply sensors 116 may be provided for monitoring the supply of
products in the various coils. These supply sensors 116 may be
configured to monitor the exact amount of product in each coil, to
monitor when the supply of product in each coil reaches one or more
predetermined monitoring levels (e.g., a restock warning level and
an empty level), or to monitor when the supply of product in each
coil is completely exhausted.
[0022] The vending machine 100 includes an access door 122 which is
used by service personnel to restock the product storage portion
102, retrieve money from the payment module 106, download system
and sales information from the VMC 110, make repairs, and perform
other service-related duties. A door switch 120 engages the access
door 122 such that the VMC 110 can detect when the access door 122
is opened.
[0023] The VMC 110 is configured to poll the various devices
provided in the vending machine system 100 in order to determine
the status of the system. For example, the VMC 110 continuously
polls the payment module 106 to determine whether any money has
been inserted into the system 100. When a customer inserts money
into the payment module 106, the payment module 106 will respond to
the VMC's polling with a message indicating the amount of money
received. Once the appropriate amount of money is received from the
customer and a selection is entered into the user interface 108,
the processor 336 instructs the product delivery mechanism 104 to
deliver the product corresponding to the customer's selection. The
amount of cash received, the amount of change returned to the
customer, and the product vended are stored in the memory 334 of
the VMC 110. Thus, the VMC 110 is able to maintain a record of
vending machine operational data, e.g. sales and cash.
[0024] In accordance with embodiments of the present invention, an
audit system 140 is provided for monitoring the vending machine
system 100. Although the audit system 140 may be provided as an
integral component of the vending machine system 100, in many
cases, the audit system 140 is a separate device that can be
installed in an existing vending machine system 100. The audit
system 140 comprises one or more interfaces for coupling the audit
system 140 to other devices. This can be accomplished using, e.g.,
a serial interface, such as a DEX or MDB port, that communicates
using a standard data protocol, such as DEX/UCS or MDB/ICP.
[0025] In the embodiment shown, the audit system 140 comprises a
DEX interface 210 and a MDB interface 212, which couple to a
corresponding DEX interface 310 and MDB interface 312 on the VMC
110. The DEX interface 210 comprises an interface which allows the
coupled devices to communicate according to the DEX/UCS protocol.
The physical connection provided by the DEX interface 210 may
comprise a 1/4 inch female socket. In this embodiment, the audit
system 140 uses the DEX interface 210 to transmit and receive
messages regarding operational data from the VMC 110. This may
include requesting and receiving DEX files, as will be described in
greater detail below.
[0026] The MDB interface 212 is an interface that complies with the
standard established as the Multi-Drop Bus/Internal Communication
Protocol (MDB/ICP), which is a serial bus interface for
electronically controlled vending machines. The illustrated audit
system 140 may use the MDB interface 212 to receive power from the
power supply 118 via the VMC 110 and to interface with peripheral
devices coupled to the VMC 110.
[0027] The audit system 140 may also be provided with a peripheral
interface 214 for directly coupling the audit system 140 to
peripheral devices without utilizing the VMC 110. This peripheral
interface to 14 may comprise, e.g., a serial interface, such as the
12C interface.
[0028] The audit system 140 also comprises an audit control system
150, which implements the control logic for operation of the audit
system 140. The audit control system 150 comprises a processor,
shown as MPU 152, which can be, e.g., an AVR ATmega128
microcontroller by the Atmel Corporation of San Jose, Calif. The
audit control system 150 may also be provided with one or more
memory devices. In the embodiment shown, the audit control system
150 comprises an EEPROM 154, a flash memory 155, and a data memory
156. The EEPROM 154 may be used to store settings for the
operational parameters of the audit system 140. The flash memory
155 may be used to store program data for execution by the MPU 152.
The data memory 156 may comprise an SRAM memory for storing
operational data retrieved from the VMC 110. In the AVR ATmega128
microcontroller, these memory devices are incorporated into the
microcontroller. In other systems, the memory devices may be
provided in separate devices.
[0029] The audit system 140 also comprises a communications
interface 142 for coupling the audit system 140 to the network 162.
The communications interface 142 may comprise any of a variety of
types of communication interfaces, both wired and wireless. A wired
interface may comprise any of a variety of well-known interfaces
for coupling to wide-area networks via a wire, cable, fiber-optic,
or other physical media for transmitting analog or digital data. A
wireless interface may comprise any of a variety of well-known
interfaces for establishing a wireless link to a wide-area network.
The wireless interface may comprise a long-range wireless
interface, such as a radio frequency (RF) modem for transmitting
data using a variety of communication protocols, e.g., General
Packet Radio Service (GPRS), Cellular Data Packet Data (CDPD), Code
Division Multiple Access (CDMA), and Time Division Multiple Access
(TDMA). In other embodiments, the communications interface 142 may
comprise a short-range wireless interface using a short-range
wireless protocol such as, e.g., IEEE 802.11 (WiFi), IEEE 802.15
(Bluetooth), and IrDA, as well as other types of RF transmissions,
such as on the 900 MHz and 2.4 GHz frequencies. The short-range
wireless interface may be provided for communicating with a base
station receiver (not shown), which, in turn, is coupled to the
wide-area network 162 for communication with the host system 160.
The base station receiver may be used to provide wide-area network
connectivity for a plurality of vending machine systems, which
communicate with the base station receiver via the short-range
wireless interfaces. This can serve to decrease the cost of the
network connectivity provided in each vending machine system.
[0030] The host system 160 can communicate with the audit system
140 using a communication protocol, such as, e.g., User Datagram
Protocol (UDP), File Transfer Protocol (FTP), Transmission Control
Protocol (TCP), or the like, as would be understood by one of
ordinary skill in the art.
[0031] The audit system 140 is configured to collect operational
data from the VMC 110. This operational data may comprise
information regarding sales (e.g., a coil name, unit price,
cumulative sales total, and cumulative cash total), cash collection
(e.g., "cash in": total cash inserted into the vending machine;
"cash out": total cash output by the vending machine as change;
"bills to stacker": total bills that are in the bill stacker; "coin
to box": total coins that are in the coin box; "tube cash": total
cash transferred to the coin tubes; "card cash": total "cashless"
monetary value received by the vending machine), temperature, etc.
In vending machine systems utilizing the DEX protocol, the audit
system 140 collects operational data by requesting a DEX file from
the VMC 110.
[0032] Under the DEX standard, the VMC generates an audit report
file which includes information regarding the operation of the
vending machine. This audit report comprises an ASCII text file
including a series of lines containing audit information. The audit
report also includes a header, a trailer, and a redundancy check,
such as a checksum. Each line in the audit report file begins with
an identifier, such as ID1, CA2, CA3, etc. The identifier
identifies the type of data the line will provide. Each data field
in each line is delimited by an asterisk (*).
[0033] The audit system 140 stores a set of data collection
parameters which are the settings which govern the collection of
operational data by the audit system 140. In the illustrated
embodiment, the audit control system 150 is configured to
interrogate the VMC 110 to request predetermined types of
operational data. This interrogation occurs on a predetermined
interrogation schedule. For example, the audit control system 150
may be configured to interrogate the VMC 110 to retrieve "cash in"
and sales information every 10 minutes.
[0034] In order to transmit operational information regarding the
vending machine system 100, the audit system 140 is configured to
transmit reports to the host system 160 via the network 162. In
accordance with some embodiments, the audit system 140 transmits
three types reports: scheduled reports, alert reports, and on
demand reports.
[0035] The scheduled reports provide a predetermined set of
operational data to the host system 160 on a scheduled, periodic
basis. The scheduled reports may include operational data retrieved
from a plurality of interrogations. For example, the audit control
system 150 may be configured to transmit a sales report once per
day. This sales report would include the operational data collected
from all the DEX interrogations over the previous 24 hours.
[0036] The alert reports provide a predetermined set of operational
data in response to the detection of an alert condition in the
vending machine system 100. The audit control system 150 may be
configured to immediately transmit one or more alert reports in
response to detection of various alert conditions. For example, if
the temperature sensor 132 detects that the temperature within the
vending machine system 100 has passed beyond a predetermined
acceptable range of temperatures, the audit control system 150 will
immediately transmit a temperature alert informing the host system
160 of the situation. The audit control system 150 may also be
configured to transmit a door alert if the door sensor 130 detects
that the access door 122 has been opened.
[0037] The on demand reports provide a set of operational data in
response to receipt of a request for that data from the host
system. For example, the host system may transmit a query to the
audit control system 150 requesting the current amount of cash
available. If the audit control system 150 already has the
requested data in the data memory 156, the audit control system 150
will immediately respond to the host system 160 with the requested
data. If the data is not available, then the audit control system
150 will request the data from the appropriate device, such as,
e.g., the VMC 110, and then will transmit that data to the
requesting host system.
[0038] The audit system 140 may include a door sensor 130, which is
used to detect the state of the access door 122 for the vending
machine system 100. Although it is possible to implement a door
sensor by installing a separate door switch dedicated to the audit
system 140, this would incur additional costs for the door switch
hardware and for the labor to install the door switch. In addition,
by utilizing the same door switch as the VMC, the audit system 140
is able to detect what the VMC believes the access door's state is.
Accordingly, it would be desirable to utilize the existing door
switch 120, rather than install separate hardware.
[0039] FIG. 6 shows a method of monitoring operation of a vending
machine system, in accordance with embodiments of the present
invention. In step 601, a door circuit for a vending machine access
door is monitored to determine whether the access door is open or
closed. In step 602, if a power loss in the door circuit is
detected, then in step 603, backup power is applied to the door
circuit. In step 604, the door circuit continues to be monitored
using the backup power.
[0040] FIG. 2 is a simplified schematic illustrating the operation
of a conventional door switch 120. Two lines 201a-201b connect the
VMC 110 and the door switch 120 to form a door circuit 202. The VMC
110 includes a VMC door sensor 330, which receives power from a
power supply 118. The VMC door sensor 330 applies a predetermined
voltage to the first line 201a, typically 5 V (V+). The second line
201b remains at ground. In some vending machine systems, when the
access door 122 is closed, the door switch 120 is also closed,
thereby shorting the voltage line to ground. The VMC 110 detects
this change and recognizes this as an indication that the access
door 122 is closed.
[0041] In other vending machine systems, the door switch 120 may
operate in different ways. For example, when the access door 122 is
closed, the door switch 120 is open, thereby leaving the voltage
line 201a high. In these types of systems, the VMC 110 will
recognize that when the voltage line 201a is shorted to ground, the
access door 122 is in an open state. Based on the open or closed
door detection, the VMC 110 may be configured to respond in various
ways, such as by placing the vending machine system 100 into
service mode.
[0042] FIG. 3 shows the use of an audit system door sensor 130 with
an existing door switch 120, in accordance with embodiments of the
present invention. Here, the audit system door sensor 130 is
coupled to the door circuit 202 in parallel with the VMC door
sensor 330. Thus, the audit system door sensor 130 can sense the
changing voltage in the door circuit 202 in the same way as the VMC
110. In some embodiments, the door circuit 202 and door sensor 130
are optoisolated from the rest of the audit system 340. This can
help to avoid damage to the logic in the audit system 340 in the
event of a power surge in the door circuit 202.
[0043] The audit system door sensor 130 can be coupled to the door
circuit 202 in a variety of ways. For example, lines 201a-201b can
be spliced and joined to lines 204a-204b leading to the audit
system door sensor 130. In other embodiments, the audit system door
sensor 130 may be provided with a pair of input ports for coupling
with the two lines emerging from the VMC 110 and a pair of output
cables for coupling with a pair of input ports on the door switch
120.
[0044] The power supply 118 for the vending machine system 100
typically receives its power from an AC outlet in the facility
where the vending machine system 100 is installed. A problem may
arise when there is an interruption to the power supply to the VMC
110. The interruption to the power supply may occur for a variety
of reasons, such as, e.g., a power failure in the facility, the
power cord for the vending machine 100 being unplugged from the AC
outlet, or a failure in the power supply 118. As a result of the
loss of power, regardless of the status of the access door 122,
both lines 201a-201b will effectively be drawn to ground because no
voltage is being applied to the door circuit 202. Thus, neither the
VMC 110 nor the audit system 140 will be able to determine the
state of the access door 122.
[0045] FIG. 4 shows a retrofitable door sensor 430 that can
continue to monitor the status of the access door 122 even when the
VMC 110 ceases to power the door circuit 202. In this embodiment,
when the VMC 110 is powering the door circuit 202, the door sensor
430 passes the applied voltage from the VMC 110 through to the door
switch 120. If the audit system 440 detects that a voltage is no
longer being applied by the VMC 110, the audit system 140 will
supply power to the door circuit 202 using a battery backup. Thus,
the audit system 140 will continue to be able to monitor the state
of the access door 122, regardless of the state of the power supply
118.
[0046] As described above, conventional door circuits 202 have two
lines, a voltage line and a ground line. However, different vending
machine designs may configure the door switches in different ways.
For example, the door switches in some vending machines may be
configured such that when the door is opened, the circuit is open.
In other vending machines, when the door is opened, the circuit is
closed. Thus, when an audit system 140 having a door sensor 130 is
installed in an unfamiliar vending machine system 100, the audit
system 140 cannot assume what state of the door circuit 202
corresponds to an open access door 122.
[0047] In accordance with embodiments the present invention, the
audit system 140 may be configured to perform an initialization
process in which the audit system 140 detects the state of the door
circuit 202 corresponding to each state of the access door 122. In
one embodiment, an installer first installs the audit system 140
into the vending machine system 100, including coupling the door
sensor 130 to the door circuit 202. Then, the installer powers on
the audit system 140 while keeping the access door 122 open. Upon
initial power on, the audit control system 150 performs an initial
configuration and initialization process, which includes detection
of the state of the door circuit 202. As a result of this
initialization process, the audit control system 150 will associate
the initial detected state of the door circuit 202 with the open
state of the access door 122. This association can be stored in a
nonvolatile memory of the audit system 140, so that the audit
control system 150 will be able to continue to correctly recognize
the state of the access door 122.
[0048] In other embodiments, the initialization process may be
performed in different ways. For example, the audit system 140 may
be provided with an initialization button. When this initialization
button is depressed, the audit control system 150 will detect the
state of the door circuit 202 and associate that with an open
access door state. Other variations are possible.
[0049] Installation costs can add significantly to the overall cost
of installing an audit system 140 into an existing vending machine
system 100. In addition, mistakes made during the installation
process can render the audit system 140 partially or completely
inoperable, thus requiring an additional visit from service
personnel in order to correct the mistakes. One potential source of
installation error is the improper connection of the door sensor
132 to the door circuit 202. When attempting to tap into the wires
connecting the VMC 110 in the door switch 120, is often difficult
to discern which cable is the voltage line and which cable is the
ground. In many cases, both cables are black and otherwise visibly
indistinguishable. It may be possible to detect the voltage cable
by using a voltmeter or other detection device, or by using trial
and error to determine the proper connection of wires. However,
these methods add to the installation time and require additional
training of the installation personnel, thereby creating the
potential for operator error.
[0050] In accordance with some embodiments, the audit system 140
may be configured to monitor the door circuit 202 regardless of the
order in which the cables are coupled to the audit system 140.
Thus, the installer does not need to determine which cable is the
voltage line and which is the ground. FIG. 5 shows one embodiment
of a door sensor 530 for automatically detecting the voltage line.
As shown in FIG. 5, the VMC 110 has two lines 501a-501b to be
connected to the door switch 120, but it is unclear which line is
the voltage line and which line is the ground line. The door sensor
530 includes a sensor circuit comprising five Schottky diodes
504a-504e. The sensor circuit pulls the voltage up to terminal 506,
where it is detected by monitor logic 508. Because the door switch
120 operates to simply open or close the circuit between lines 501a
and 501b, the order in which the lines 501a-501b are coupled to the
door switch 120 is irrelevant. The monitor logic 508 detects
whether the voltage from the VMC 110 remains high or is drawn to
ground by the closure of the door switch 120, as described above.
Also, as described above with respect to FIG. 4, a backup battery
may be provided for supplying a +5V voltage across the door switch
120 in the event of a power failure.
[0051] In accordance with some embodiments, the audit system 140
may be configured to implement a timer for reporting the door
status. This timer can be used to avoid repeated "door open"
messages in response to multiple repeated opening and closing of
the access door over short periods of time. This may be caused, for
example, if the service technician slams the access door closed,
causing the access door to bounce slightly before settling into the
fully closed position. This bounce may cause the door sensor to
first detect a closure of the access door, immediately followed by
an opening of the door and another closure. This may result in the
audit system transmitting three separate messages to the host
system. In another possible scenario, the service technician opens
the access door briefly, but then closes it so that he or she can
return to the supply truck to retrieve some essential item. The
service technician will then return and open the vending machine
door again within a few minutes. As with the previous example,
multiple "door open" messages may be transmitted to the host system
in this situation, even though this type of temporary door closure
event need not be monitored.
[0052] In accordance with one embodiment, a timer begins each time
the access door is open. When the door is first opened, the audit
system will transmit a "door open" message to the host system.
After a predetermined period of time (e.g., 30 minutes), the audit
system will transmit a second message to the host system indicating
the current state of the access door and the length of time that
the door has been in that state. In one example, a technician opens
the access door for 1 minute, then closes it, goes to the supply
truck, returns to open the access door again 5 minutes later, and
then completes the servicing of the vending machine in 10 minutes.
In this case, the audit system will report the initial opening of
the door and will transmit a follow-up message 30 minutes later.
This follow-up message will indicate that the current state of the
access door is closed and that the door has been in this state for
14 minutes. So long as the access door remains closed, no further
door alert messages will be transmitted. If the access door remains
open at the time of the follow-up message, the follow-up message
will indicate this and the timer will be reset to transmit another
follow-up message in 30 minutes.
[0053] Embodiments of the present invention may provide various
advantages not provided by prior art systems. In particular,
various embodiments may improve the accuracy with which an audit
system can monitor the operation of a vending machine system. In
addition, some embodiments may improve the ease with which audit
units can be installed and reduce the chances of installation
mistakes. This can, in turn, reduce labor costs for service
personnel and improve the ability of the audit system to
continuously monitor the vending machine.
[0054] In accordance with embodiments of the present invention, the
presence of malfunctioning door switches can be more readily and
effectively detected by transmitting door status information to the
host system using the same door switch as the VMC. In addition,
some embodiments can be implemented in order to track the
performance of service personnel by monitoring the length of time
the access door is open during any particular service visit. In
other embodiments, the door status information may also be used to
reconcile sales data by providing the host system with information
regarding the date and time the vending machine was restocked. This
information is provided without requiring that the service
personnel manually press a "restock" button in the vending machine.
In yet other embodiments, the door status information may be used
to prevent theft and vandalism by enabling a host system to
immediately detect when an access door is opened at unexpected
times, e.g., late at night. In yet other embodiments, the door
status information may be used to report when a machine is serviced
by field technicians.
[0055] While the invention has been described in terms of
particular embodiments and illustrative figures, those of ordinary
skill in the art will recognize that the invention is not limited
to the embodiments or figures described. For example, in many of
the embodiments described above, the vending machine system
dispenses physical products, such as drinks or snack foods, to
customers in exchange for payment. In other embodiments, the
products vended by the vending machine may take other forms, such
as, e.g., a data download to a user's portable electronic device,
or a service. It will be understood that the vending machine system
may comprise any type of point-of-sale device and need not be
limited to only those devices that deliver tangible products to
customers.
[0056] In addition, the audit system may take various forms. In
some embodiments, the audit system including the door sensor
circuitry and logic are provided as a single installable component,
like a "black box." In other embodiments, the audit system may
comprise multiple components performing a variety of functions. The
audit system may be retrofitted to an existing vending machine
design, or may be an integral part of the system art initial
assembly.
[0057] The program logic described indicates certain events
occurring in a certain order. Those of ordinary skill in the art
will recognize that the ordering of certain programming steps or
program flow may be modified without affecting the overall
operation performed by the preferred embodiment logic, and such
modifications are in accordance with the various embodiments of the
invention. Additionally, certain of the steps may be performed
concurrently in a parallel process when possible, as well as
performed sequentially as described above.
[0058] Therefore, it should be understood that the invention can be
practiced with modification and alteration within the spirit and
scope of the appended claims. The description is not intended to be
exhaustive or to limit the invention to the precise form disclosed.
It should be understood that the invention can be practiced with
modification and alteration and that the invention be limited only
by the claims and the equivalents thereof.
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